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用自发熔化渗透法制备高TiC含量 (～ 75vol% )的TiC/NiAl复合材料 ,研究了渗透温度和渗透时间对TiC/NiAl复合材料微观组织形成、硬度及断裂性能的影响。采用XRD和TEM /EDS分析了复合材料的相组成、微观结构和NiAl相与TiC颗粒在高温渗透过程中的互溶情况。结果表明 :自发熔渗法是制备致密的TiC/NiAl复合材料的有效方法 ,适当提高渗透温度 ,可大大缩短渗透时间。在完成渗透获得致密组织的前提下 ,渗透温度和渗透时间对TiC/NiAl复合材料的硬度及断裂韧性无显著影响。NiAl相和TiC颗粒结合良好 ,是渗透后复合物的仅有组成相。TiC少量地溶于NiAl,溶解度随渗透时间增长而增大 ,且在TiC颗粒外层 ,发现有少量的Al和微量的Ni。
The TiC / NiAl composites with high content of TiC (~ 75vol%) were prepared by spontaneous melting infiltration method. The effects of infiltration temperature and infiltration time on the microstructure, hardness and fracture properties of TiC / NiAl composites were investigated. The phase composition, microstructure and intermixing of NiAl phase with TiC particles during high temperature infiltration were analyzed by XRD and TEM / EDS. The results show that spontaneous infiltration method is an effective method for preparing compact TiC / NiAl composites. The infiltration temperature can be greatly shortened by properly increasing the infiltration temperature. The infiltration temperature and infiltration time have no significant effect on the hardness and fracture toughness of the TiC / NiAl composites under the premise of achieving the infiltration of dense tissue. NiAl phase and TiC particles combine well and are the only phase of the composite after infiltration. TiC dissolves a little in NiAl, solubility increases with the infiltration time, and in the outer layer of TiC particles, a small amount of Al and trace Ni are found.